Driverless trains

How have driverless trains still not replaced normal ones? I get the situation with cars, as they need approvals and laws, but trains are different.

Moscow metro directors say that the intervals will be longer than with traditional drivers, but this can’t possibly be real. There is much more communication between driverless trains that between normal ones, so the intervals would be the same or smaller. Sure, the technology may need upgrading, but this is a no-brainer for a worthwhile investment.

I’ve been in several driverless trains: Paris’s airport shuttle, Milan’s M5 line, London’s DLR, the Turin metro, Pisa’s airport shuttle. They all work really well and insure more security than regular trains.

Don’t procrastinate, automate!